


Dream Big

by wellthatjusthappend



Series: Story Requests [19]
Category: Batman - All Media Types
Genre: Alternate Universe - Merpeople, Claiming, Explicit Consent, I don't go into detail, M/M, Not so much my thing but I tried my best, Oviposition, Short, Size Difference, Size Kink, Stuffing, Tumblr Prompt, Weird Biology, a 'clutch' is a collection of one or more eggs in this story, ish?, my Mer are never safe because what's the fun in that?, not my main merfolk au, other relationships teased
Language: English
Status: Completed
Published: 2019-06-25
Updated: 2019-06-25
Packaged: 2020-05-19 07:37:52
Rating: Explicit
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 1,362
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/19352458
Author URL: https://archiveofourown.org/users/wellthatjusthappend/pseuds/wellthatjusthappend
Summary: “Oh Jay, you have to find an older sire, at least once. You’ll love it; I’ve never been so full," Dick had sighed with content.Jason had been so so fucking jealous, but not this year, dammit.





	Dream Big

**Author's Note:**

> Prompt: _So mer what if instead of dieing they just keep growing and getting bigger as they age? I mean gaint mer Slade (or ra's) beating Jason in a claiming fight and splitting his slit open with a thick cock to fill him with cum or eggs. (I saw your mer stories and I love them! Dangerous mer are my favorite.)_
> 
> So I've never written Oviposition before (though my Mer are often kinked for it) but I gave it a shot. 
> 
> Note: in this universe sexes are a little flipped. A sire is the one with the eggs and carries them until they're fully formed and then lays them in a brooder for fertilization and gestation. Or that's kind of how it works in my head? Doesn't really matter, it's mostly PWP anyway.

Bruce would say Jason was hunting for trouble.

But just because the older Mer kept an eye out for him when he was still young didn’t make him Jason’s brooder. And anyway, Jason  _ knew _ he was hunting trouble. That was kinda the point. 

Because Jason liked brooding hatchlings as much as the next Mer- it was a special pleasure for their kind- but most of the sires Jason knew were young and could only give him one egg maybe two. But last season- fucking last season,  _ Dick _ had come back from his wanderings with a beautiful swell to his stomach, bloody marks on his skin, and a dreamy expression.

_ “Oh Jay, you have to find an older sire, at least once. You’ll love it, I’ve never been so full,” _ he’d told him. And if Jason had been jealous before- and he totally still was- he could barely contain himself when Dick managed to brood 6 whole eggs to term from one encounter. 

Now there was a rumour that there was a beast in this area and Jason was going to find it while Dick was too busy to dazzle it with his pretty scales and scars. Jason didn’t get many opportunities for the limelight, and the only hatchling he’d carried before was with a friend, but he was determined that this next brood would be  _ his.  _

Jason followed the slight scuffs on the rocks, stray scales left behind for a Mer scratching up against the rough rock, a sure sign that they were searching for a safe place to deposit their eggs. He picked up one of the coppery scales and marveled at the size of it. Mer didn’t have any natural predators besides each other -and humans, he supposed- so if they were tough enough to survive, Mer would keep on growing seemingly indefinitely. Now Mer were aggressive enough that this pretty much always was cut short, but Jason had once caught a glimpse of Ra’s al Ghoul and he’d been as big as a whale. 

He wondered how old this Mer was. 

Swimming a little faster, Jason kept low to the sand searching for more dropped scales. 

Then the sand all around Jason erupted as the Mer that had been buried just beneath the surface dozing, awoke and threw him down against the ocean flood.

Jason shrieked instinctively in outrage and bit and slashed at the arm holding him down, but the cuts just healed before his eyes.

“Now what have we here?” rumbled a deep voice and Jason got his first good look at the Mer and  _ holy shit _ he was in trouble, the silver haired Mer was at least 2 or 3 times as big as Bruce who was definitely older now, “have you lost your way, kid?”

“Not a hatchling,” Jason snapped, fins flaring out aggressively. 

“Mmm, I guess you’re right,” mused the beast above him, lightly stroking where Jason’s slit had already loosened in his excitement.

“Hands off bastard,” Jason flashed his teeth and tried to slap him with his tail, “who says I’m even interested in your dirty old eggs, geezer.”

“No?” The Mer smiled, and Jason caught himself staring at an attractive face, made even more so by the missing eye so blatantly displayed, “my mistake. My name’s Slade.”

“Didn’t ask,” Jason hissed as he was released and he immediately flipped away, intending to get out of reach.

...only to be caught again and held still with impossible strength, this time in the open water with nothing to leverage.

“Young brats have no manners,” Slade mused, “It’s polite to offer your name in return.”

“Fuck you,” Jason spat.

“Mmm, not quite,” Slade rumbled in amusement. 

All the warning Jason got was a flash of movement and then Slade’s mouth was closing over his shoulder. Jason screeched in pain, but he couldn’t jerk away in the hold. The taste of his own blood filled the water and he felt himself starting to get slick and dizzy with desire. 

So powerful. So dominant. 

“Now,” Slade said as he pulled back enough to drag his tongue against the wound, “What was your name again, little one?”

“Jason,” he whimpered, trying to arch into the touch. 

“And why were you here?”

“Looking for you,” Jason panted, nibbling at the tough skin against his face, “Wanted you.”

“Yeah? Little brooder hunting for a nice clutch to nest over?” this time when fingers probed his opening, Jason twisted to offer himself up to the touch. 

He threw his head back and crooned, low and long when the fingers breached him, dignity thrown out the window. He didn’t care; It was only fingers, but they were thick and long and already making him feel that tantalizing stretch. 

“Geez, kid, look at you,” Slade’s voice had gotten low and gruff, “Too young to know what you’re asking for. Probably never carried a proper clutch before.”

“Shut up, I’ve carried hatchlings before. I told you; I’m not that young,” he didn’t mention that it had only been the one. 

“Tell you what, kid,” Slade rumbled, biting his ear as he withdrew his fingers and laid Jason down against the sand again, “I’ll show you what a proper clutch is supposed to feel like and then you tell me what you know.”

“I know you’re an ass- FUCK,” Jason smacked his head against the sand as Slade entered him. 

_ Too big _ ! A part of him insisted while another part chorused,  _ too good _ !

“Hah, so slick,” Slade hummed, holding Jason’s tail steady so he couldn’t wriggle away, “You wanted this bad kid. Pity that oaf who looks after you never takes what’s on offer.”

“Nh,” Jason groaned the length steadily breached him in steady incremental thrusts that knocked the air right out of him. 

“I know you’re one of Bruce’s pretty little mer. Fool guards you lot like his territory and won’t let anyone else have a taste but won’t fill you up himself. It was only a matter of time before someone took a needy little thing like you and put your body to use.”

Jason wasn’t usually into dirty talk with his partners, but he found he was super into it (even if the idea of Bruce ever wanting any of them was ludicrous). Maybe he was just high on hormones from the feeling of being claimed by someone so much bigger and stronger than him. Jason was pretty big himself, much larger than most in his age group. He wasn’t used to anyone but Bruce being larger and stronger than he was. Now Slade was there positively dwarfing him and making him take his brood and Jason was in heaven. 

For just this moment at least, he wanted to be Slade’s boy. 

When the first egg pushed inside, Jason came hard, his body lighting up all over with pleasure. 

“Fuck, you’re perfect,” Slade crooned approvingly, stroking his face. Jason leaned into the touch, not caring if he looked desperate, “easy now, you’re not done yet.”

They certainly weren’t.

With every egg that stretched him open, Jason felt like he somehow achieved a new height of pleasure. The soft but firm shape of them inside him seemed to drag against every good nerve in a constant pressure. Mer’s bodies were made for this and Jason didn’t know how he was ever going to go back to carrying just one egg. 

“There you go,” Slade soothed, rubbing Jason’s rounded stomach possessively as the ninth egg slid into place and Jason sobbed as he was overwhelmed by the feeling, “so good for me, so lovely.”

Jason grunted in discomfort as Slade pulled out of him and snapped his teeth at him testily when Slade tried to tease again with his fingers. 

“Quit that,” he growled and then groaned as tensing proved to make the pressure of the eggs inside him known and bright lights danced behind his eyes. 

“Stuffed full of my brood and still fighting? I knew I liked you,” Slade said approvingly, the huge Mer completely surrounding him in his mass. 

“Fucking geezer,” Jason said half heartedly. 

“Maybe your next season I’ll come find you again.”

Maybe Jason would come find  _ him _ again. 

**Author's Note:**

> Hope you liked it!
> 
> If you've ever wanted to send a story request, feel free! Besides AO3, I'm on [Tumblr](https://wellthatjusthappend.tumblr.com/mywriting),[DA](https://www.deviantart.com/wellthatjusthappened), and Discord. Same username. 
> 
> If you want a continuation of a story, you can always send another prompt. FQAs listed on my [writing](https://wellthatjusthappend.tumblr.com/mywriting) page.


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